C&B
This is something I am in the process of doing. I bought a flat 4 yrs ago and rented it out. 2 years later I released a small amount of equity out of it to buy a house which is now rented out to. equity paid (solicitors fees and such like as it hadnt gone up in value so much). I am now in the process of releasing the equity from the house to buy another one for me to live in.
With buy to let I think the rent has to be 120% of the mortgage payment each month so that it covers you should the property be empty for a month etc. Im sure Comedy Dan or someone like that could help there.
I have the flat on repayment and the house was on repayment but just changing to interest only. New one will be on interest only to for now. Reason been is the house i currently have is rented to my sister at the moment who is skint so I have to make up remaining mortgage payment every month. Changing to interest only will reduce payments so her rent will cover it.
hth
Ben